Research On Q450NQR1 High Strength Sheet Metal Forming Springback And Application Of Shallow Drawing

Recent years, in the condition of energy saving, environmental protection has become the most important issue to be resolved under the premise that security is guaranteed in vehicle industry. With China's rapid development of high-speed railway transportation, lightweight body technology train has been taken more and more attention. High strength steel due to its high strength and the demand for reduce vehicle weigh been widely acknowledged by train manufacturers. Q450NQR1 high strength sheet metal due to its high safety, and crashworthiness qualities has been widely used in trains, ships and other fields. However, the high strength sheet metal has larger springback and distortion than common rail train forming sheet, seriously affected the shape and size of stamping and welding assembly accuracy and reliability of follow-up and so on. So effectively predict and control the rebound part during forming process, become the first problem to be solved in Q450NQR1 high strength sheet application. This paper is mainly focused on the following aspects:First, research on the deformation process and springback of the typical V-shaped parts and U-shaped parts with a flange. A series of springback numerical simulation experiments of U&V-shaped part are carried out. The factors influencing sheet springback are analyzed in this paper, which include correction force, material property, relative bending radius, die gap, blank holder force etc. Drawing the project curve between these factors and springback amount and summarizing a constructive conclusion.Second, this paper discussed the difference and application between physical drawbead and equal effective drawbead. Based on the equal effective draw-bead, through the orthogonal experimental design method, a mass of simulation were carried out to build the relationship between drawbead restraining force combinations and springback. Using multiple nonlinear regression method to combine the analysis results, finally find the optimal parameters of drawing resistance force combinations. All these conclusions could be a valuable reference in both die design and correction.The third, die surface compensation method which is used to control the springback is preliminarily studied. Used the springback compensation planning of DYNAFORM to compensate the model that has finished the forming and springback calculation. After several rounds of compensation, the result of springback was significantly improved.Finally, use the C70 side door panel simulation as an example of Q450NQR1 high strength sheet metal forming to test and verify action of the optimization of the resistance drawbead combination of drawing and geometry springback. And also provide a reference of Q450NQR1 level high strength sheet metal for its future application and mold design.In summary, the research puts forward an effective method for forming Q450NQR1 high strength steel sheet rebound control. Starting from both parameter control and compensation, springback can be reduced by integrating simulation with optimization. The period of die adjustment could be shortened, and product research expenditure could be decreased. It is absolutely a significant meaningful way in theory and practical engineering application of Q450NQR1 level high strength sheet metal.